A Waterproof Ion-Conducting Fluorinated Elastomer with 6000% Stretchability, Superior Ionic Conductivity, and Harsh Environment Tolerance

The development of ionic conductors with extreme stretchability, superior ionic conductivity, and harsh-environment resistance is urgent while challenging because the tailoring of these performances is mutually exclusive. Herein, a hydrophobicity-constrained association strategy is presented for fabricating a liquid-free ion-conducting fluorinated elastomer (ICFE) with microphase-separated structures. Hydrophilic nanodomains with long-range ordering and selectively enriched Li ions provided high-efficient conductive pathways, yielding impressive room-temperature ionic conductivity of 3.5 x 10(-3) S m(-1). Hydrophobic nanodomains with abundant and reversible hydrogen bonds endow the ICFE with superior damage-tolerant performances including ultrastretchability (>6000%), large toughness (17.1 MJ m(-3)) with notch insensitivity, antifatigue ability, and high-efficiency self-healability. Due to its liquid-free characteristic and surface-enriched hydrophobic nanodomains, the ICFE demonstrates an extreme temperature tolerance (-20 to 300 degrees C) and unique underwater resistance. The resultant ICFE is assembled into a proof-of-concept skin-inspired sensor, showing impressive capacitive sensing performance with high sensitivity and wide-strain-range linearity (gauge factor to 1.0 in a strain range of 0-350%), excellent durability (>1000 cycles), and unique waterproofness in monitoring of complex human motions. It is believed that the hydrophobicity-constrained association method boosts the fabrication of stretchable ionic conductors holding a great promise in skin-inspired ionotronics with harsh-environment tolerance.

Automated summary

This study presents a hydrophobicity-constrained association strategy for fabricating a liquid-free ion-conducting fluorinated elastomer (ICFE) with superior stretchability, ionic conductivity, and resistance to harsh environments. The ICFE demonstrated high room-temperature ionic conductivity and superior damage-tolerant performances with ultrastretchability, large toughness, antifatigue ability, and high-efficiency self-healability. The ICFE also showed extreme temperature tolerance and unique underwater resistance. The ICFE was applied to a skin-inspired sensor, exhibiting impressive capacitive sensing performance and excellent durability.